resistor100k 220k Screen grid (g2) resistor 390k 1M Cathode bias resistor 1k 2k2 In each case the cathode bias resistor should be boot-strapped to 0V with a 47µF 50V electrolytic. The grid leak resistor (g1) can be 1M or (shown in more detail in the data booklet). In this only two variations for resistor values are www.datasheetarchive.com/files/maplin/products/02/4/96prodd.htm